The present invention relates to light assemblies, and more particularly to light assemblies providing a linear or two-dimensional output.
LEDs (light emitting diodes) have become an increasingly popular choice for lighting sources due to their high efficiency and long expected lifetime. LEDs however are point sources of light and, as a result, produce harsh, high-glare light patterns. LEDs also can product undesirable shadowing and “hot spots” (i.e. areas of relatively intense illumination) on the illuminated surface. These issues are particularly noticeable and problematic when the illuminated surface is a critical surface, such as a work surface or a product display.
In view of the foregoing issues, the light from the LEDs may be mixed before emission from a light assembly or luminaire. A variety of methods are available for providing mixing, also known as secondary mixing, and emitting the light in a linear pattern. The most traditional method is to include a secondary lens including diffusing optics, diffusing geometries, or both. Another traditional method includes edge lighting a light pipe and then extracting the light through a surface perpendicular to the light-injection surface. This method often is used for backlit displays such as LCD (liquid crystal display) screens.
However, these methods typically require the LEDs to be spaced closely together in order to work effectively. As a result, these methods require a greater number of LEDs than is necessary to meet the total light emission objectives of the light assembly.